Firstly the Investigators aim at investigating the role of endogenous female sex hormones and HT in relation to insulin resistance, whole body fat oxidation and -energy expenditure, changes in visceral fat mass and fat free mass after oophorectomy. Secondly, the Investigators wish to study the molecular mechanisms behind the oophorectomy-induced insulin resistance with a focus on insulin signaling in skeletal muscle and fat tissue. Lastly, the investigators aim to explore whether exercise and/or HT can compensate for loss of endogenous female sex hormone production by maintaining IS and metabolic activity, hereby preventing future incidents of metabolic disease in relation to menopause.